Implement structured logging with slog

- Replace zerolog with Go's standard slog package
- Add ColorHandler for terminal color output
- Add context-aware logging system
- Format attributes on the same line as log messages
- Use green color for INFO level logs
- Set up context value extraction helpers

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

gemini/files.go

@@ -1,114 +0,0 @@
-package gemini
-
-import (
-	"fmt"
-	"net/url"
-	"os"
-	"path"
-	"path/filepath"
-	"strings"
-
-	"gemini-grc/common/snapshot"
-	"gemini-grc/logging"
-)
-
-// sanitizePath encodes invalid filesystem characters using URL encoding.
-// Example:
-// /example/path/to/page?query=param&another=value
-// would become
-// example/path/to/page%3Fquery%3Dparam%26another%3Dvalue
-func sanitizePath(p string) string {
-	// Split the path into its components
-	components := strings.Split(p, "/")
-
-	// Encode each component separately
-	for i, component := range components {
-		// Decode any existing percent-encoded characters
-		decodedComponent, err := url.PathUnescape(component)
-		if err != nil {
-			decodedComponent = component // Fallback to original if unescape fails
-		}
-
-		// Encode the component to escape invalid filesystem characters
-		encodedComponent := url.QueryEscape(decodedComponent)
-
-		// Replace '+' (from QueryEscape) with '%20' to handle spaces correctly
-		encodedComponent = strings.ReplaceAll(encodedComponent, "+", "%20")
-
-		components[i] = encodedComponent
-	}
-
-	// Rejoin the components into a sanitized path
-	safe := filepath.Join(components...)
-
-	return safe
-}
-
-// getFilePath constructs a safe file path from the root path and URL path.
-// It URL-encodes invalid filesystem characters to ensure the path is valid.
-func calcFilePath(rootPath, urlPath string) (string, error) {
-	// Normalize the URL path
-	cleanPath := filepath.Clean(urlPath)
-
-	// Safe check to prevent directory traversal
-	if strings.Contains(cleanPath, "..") {
-		return "", fmt.Errorf("Invalid URL path: contains directory traversal")
-	}
-
-	// Sanitize the path by encoding invalid characters
-	safePath := sanitizePath(cleanPath)
-
-	// Join the root path and the sanitized URL path
-	finalPath := filepath.Join(rootPath, safePath)
-
-	return finalPath, nil
-}
-
-func SaveToFile(rootPath string, s *snapshot.Snapshot, done chan struct{}) {
-	parentPath := path.Join(rootPath, s.URL.Hostname)
-	urlPath := s.URL.Path
-	// If path is empty, add `index.gmi` as the file to save
-	if urlPath == "" || urlPath == "." {
-		urlPath = "index.gmi"
-	}
-	// If path ends with '/' then add index.gmi for the
-	// directory to be created.
-	if strings.HasSuffix(urlPath, "/") {
-		urlPath = strings.Join([]string{urlPath, "index.gmi"}, "")
-	}
-
-	finalPath, err := calcFilePath(parentPath, urlPath)
-	if err != nil {
-		logging.LogError("GeminiError saving %s: %w", s.URL, err)
-		return
-	}
-	// Ensure the directory exists
-	dir := filepath.Dir(finalPath)
-	if err := os.MkdirAll(dir, os.ModePerm); err != nil {
-		logging.LogError("Failed to create directory: %w", err)
-		return
-	}
-	if s.MimeType.Valid && s.MimeType.String == "text/gemini" {
-		err = os.WriteFile(finalPath, (*s).Data.V, 0o666)
-	} else {
-		err = os.WriteFile(finalPath, []byte((*s).GemText.String), 0o666)
-	}
-	if err != nil {
-		logging.LogError("GeminiError saving %s: %w", s.URL.Full, err)
-	}
-	close(done)
-}
-
-func ReadLines(path string) []string {
-	data, err := os.ReadFile(path)
-	if err != nil {
-		panic(fmt.Sprintf("Failed to read file: %s", err))
-	}
-	lines := strings.Split(string(data), "\n")
-	// remove last line if empty
-	// (happens when file ends with '\n')
-	if lines[len(lines)-1] == "" {
-		lines = lines[:len(lines)-1]
-	}
-	return lines
-}